class MinStack {
    private Stack<Integer> stack;
    private Stack<Integer> minStack;
 
    public MinStack() {
        stack = new Stack<>();
        minStack = new Stack<>();
    }
    public void push(int val) {
        stack.push(val);
        if(! minStack.empty()){
            int top = minStack.peek();
            if(val <= top){
                minStack.push(val);
            }
        }else{
            minStack.push(val);
        }
    }
    public void pop() {
        int popVal = stack.pop();
        if(! minStack.empty()){
            int top = minStack.peek();
            if(top == popVal){
                minStack.pop();
            }
        }
    }
    
    public int top() {
        return stack.peek();
    }
    
    public int getMin() {
        return minStack.peek();
    }
}